Dynamic Dropdown Menus

Hi there, im new to the forum and currently in the process of building a website.
Unfortunetly it needs a little javascript putting in and I dont know any javascript atall.

So heres my problem:
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I want 3 drop down menus where
you change the top option, the middle menu updates (from a sql database),
you change the middle option then the bottom option updates (again from the database).
you select the 3rd option.
it searches a database for the item matching all 3 entrys
it displays the price

all without reloading the page

then you add the item to cart.

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Heres my site with fake data in the dropdowns:
http://xeon.donov.co.uk/~blinky/?a=cat_sub&cid=3&f=A3

You can make really simple ones with some basic css. I think the hover pseudoclass is css1. Here's a css one:
http://www.evolt.org/node/52030
and a javascript one:
http://javascript-array.com/scripts/simple_drop_down_menu/
They're both pretty basic. Given that you're using databases and what not I can't see why you couldn't handle these.

Edit:
Sort of didn't really read what you wanted there. Are you saying the content of the list changes depending on what you pick? If so you may need to look into ajax not javascript.